The principal objective of this research is to relate protein structure to function. Our main emphasis has been on the attempt to understand molecular features of protein nucleic acid interactions. We have begun to study proteins involved in T4 DNA replication and up to now have focused on the T4 gene 32 protein, a helix destabilizing protein which forms a complex with T4 DNA polymerase (43P) and four other proteins, 45P, 41P, 44P/62P which catalyzes DNA synthesis in vitro. To extend these studies to the T4 DNA polymerase (43P) we plan to clone, then characterize 43P and develop ways of obtaining high levels of gene 43 expression in cells transformed with plasmid or lambda phage vectors carrying the entire 43 gene. Once satisfactory amounts of 43P are available we will use limited proteolysis to cleave it into separate polypeptide domains and then investigate the behavior of these fragments with regard to polymerase and exonuclease activities, binding to DNA and to other protein required for DNA replication.